Oddly enough at one time we were shown the application forms for people applying to be our line manager; one of whom listed unicycling skills when applying for a computer management job.

The thinking behind that is perfectly logical: you want to include hobbies in your resume to give an idea that you have interests outside the office. It makes the resume more interesting and occasionally, you'll hit someone who shares the same interest. If I saw that on a resume, it'd go to the top of the pile.